BOSTON A large-scale comparative test of three anti-epilepsy drugs found the oldest was best for treating childhood absence epilepsy, in which youngsters often stare into space for up to 20 seconds many times a day.
Ethosuximide, available since the 1950s, offered the best protection for the condition. Lamotrigine fared the worst, the researchers reported in the New England Journal of Medicine.
A third treatment, valproic acid, worked nearly as well as ethosuximide, but interfered with concentration.
The generic drugs used in the study were made by Pfizer Inc. (Ethosuximide), GlaxoSmithKline Plc (Lamotrigine) and Abbott Laboratories (valproic acid).
"The older drug gives you better seizure control combined with fewer attention problems," Dr. Tracy Glauser of Cincinnati Children's Hospital in Ohio, who led the study, said in a telephone interview.
The study is the first to conclusively compare drug treatments for childhood absence epilepsy, the most common form of childhood seizures.
The condition usually begins between ages 4 and 8 in children with no other health problems. It is sometimes called petit mal epilepsy.
The study looked at 446 youngsters treated at 32 centers across the United States.
After four months of therapy, 58 percent of the children getting valproic acid and 53 percent of those getting ethosuximide were free of seizures, compared to just 29 percent given lamotrigine.
But too many valproic acid recipients continued to experience problems paying attention.
So the winner is ethosuximide, Dr. Eileen Vining of the Johns Hopkins School of Medicine in Baltimore said in a commentary. "This is an age when the newest therapy is assumed to be more effective and better tolerated than older therapies," she wrote.
Glauser said the researchers also discovered that even though there may be no outward evidence of seizures and drug therapy appears successful, EEG brainwave tests show they can be occurring.
"EEG studies are necessary to know if the kids are seizure free (because) the longer they have these types of seizures, the higher their risk of developing other types of seizures and, we think, the harder it is to control," Glauser said.
In addition, if a child has problems paying attention before treatment, drugs may not cure that.
"We still have a lot of room for improvement," he said.
(Editing by Maggie Fox and Todd Eastham)